James
Sounds like you are doing well with the canvassing, nice one!
The more you do, the more you will learn and you will become quicker and more confident. You'll get to a stage where anyone who gives you grief, you'll just reply politely and walk away; It won't even worry you.
My only advice is, when you clean a customer's house and it's filthy, make sure you charge extra (for the extra time involved).
Then if the customer is genuine and uses you again, you are on a winner, but if the customer cancels the next clean, then at least you have covered the cost of the first clean. If a customer doesn't want to pay extra for a first clean then I would be wary and would walk away, rather than clean it.
Good luck...welcome to silly season!